“There’s no doubt that Downtown Brooklyn is coming into its own as a 24/7 live-work — and shop – city center,” said Borough President Marty Markowitz.

But newcomers are already griping about a dearth of local schools, grocery stores, retail shops, timely sanitation pickup and street lighting.

“These people were promised the Manhattanization of Brooklyn by their brokers and all they got was being able to live in tall buildings,” said City Councilwoman Letitia James (D-Brooklyn), who represents most of the area.

The public-private Downtown Brooklyn Partnership estimates another 2,500 people will move in by 2013, bringing the total to 14,500.

It’s a far cry from the 400 residents who lived there 11 years ago when the area’s 16-square-block core — including Fulton Mall, MetroTech complex and the Jay and Willoughby street corridors — was a struggling business district filled with 99-cent stores.

A surge of new luxury buildings boast amenities ranging from swimming pools to rooftop decks — but come at a steep price. The average one-bedroom pad runs about $2,500-$2,800 a month while two-bedroom condos are now selling for an average of about $550,000 to $600,000.

Bram Daly, 35, who rents a one-bedroom apartment at the 80 Dekalb residential tower, said he loves his new neighborhood.

“I have a killer view,” he said. “I don’t feel like I am missing Manhattan.”

About 60 percent of the neighborhood’s new residents live in luxury rentals as the condo market has struggled due to the national credit crunch.

Officials estimate about two million more people will be visiting the area per year by 2012, following the planned opening of the Nets’ new NBA arena a half-mile away and the nearby expansion at the BAM Cultural District.

Transit and other infrastructure upgrades are in the works to compensate both projects.

Since 2006, there’s been $3.4 billion in private investment in the entire Downtown area, a 60-square-block section bounded by Tillary Street to the north, Cadman Plaza and Court Street to the west, Ashland Place to east and Atlantic Avenue to the south.

This has resulted in 5,200 residential units, 1,000 hotel rooms and 726,000 square feet of retail and office space.

However, while Downtown’s housing market strived – with the exception of 6,400 units planned at the stalled Atlantic Yards project – the national credit crunch significantly dipped into the city’s once lofty expectations for new commercial space and hotels there.

In 2007, officials estimated Downtown Brooklyn by 2012 would have 3.2 million square feet of new retail and office space and 1,800 new hotel units.

About 20 new stores have opened, bringing 500 jobs, including Aeropostle and Barney’s Co-op. And some new tenants are slated to move in later this year, including Shake Shack, Danny Meyer’s popular burger joint.